Aromatherapy uses essential oils, concentrated plant extracts, to influence mood, stress levels, and overall well-being through inhalation or topical application. Getting started is straightforward once you understand the main delivery methods, proper dilution, and a few important safety rules.
Why Inhaling Essential Oils Affects Your Mood
When you inhale an essential oil, volatile molecules travel through the nasal cavity and bind to receptors in the olfactory epithelium, the tissue high inside your nose responsible for detecting scent. Those receptors generate electrical signals that travel directly to the olfactory bulb in the brain.
What makes smell unique among your senses is that the signal bypasses the thalamus, the brain’s usual relay station, and projects straight to the cortex. From there it reaches the limbic system: the amygdala (which processes emotion and scent intensity), the hippocampus (memory), and the hypothalamus (hormone regulation). This direct wiring between scent, emotion, memory, and hormonal function is why a single whiff of lavender or eucalyptus can shift how you feel within seconds.
Choosing a Diffuser
Diffusing is the most common way to practice aromatherapy at home. The three main diffuser types work differently, and the one you pick depends on your goals.
Ultrasonic Diffusers
These use water and a vibrating disc to create a fine, cool mist. Because the oil is diluted in water, the scent is lighter and more subtle. They double as a mild humidifier and can run for hours, making them a good everyday option for small to medium rooms. The trade-off is that the water dilutes the oil’s chemical composition, so the aroma is less concentrated.
Nebulizing Diffusers
Nebulizers use an atomizer to break pure essential oil into microparticles with no water or heat involved. This preserves the oil’s full chemical profile and produces a much more potent, concentrated scent that disperses quickly across a wider area. They’re the strongest option for therapeutic use, but they consume oil faster and tend to be louder.
Heat Diffusers
Candle warmers, electric warmers, and similar devices use heat to evaporate the oil. They’re inexpensive and silent, but high temperatures can alter the oil’s molecular structure, reducing its therapeutic value. If you go this route, choose a low-heat model.
For any diffuser, start with 3 to 5 drops and adjust from there. Run the diffuser in 30- to 60-minute intervals rather than continuously. Constant exposure can desensitize your olfactory receptors, meaning you stop noticing the scent and may be tempted to add far more oil than you need.
Applying Essential Oils to Skin
Essential oils are highly concentrated and should never go directly on skin without dilution. A carrier oil acts as the base, slowing absorption and reducing the risk of irritation. A standard dilution for adults is about 2%, which works out to roughly 12 drops of essential oil per ounce (30 mL) of carrier oil. For sensitive skin or larger body areas, 1% (6 drops per ounce) is a safer starting point.
Common carrier oils include:
- Jojoba oil: Technically a liquid wax, jojoba closely mimics your skin’s natural sebum. It absorbs well, has a mild nutty scent, and resists going rancid, giving it a long shelf life.
- Sweet almond oil: Lightweight, affordable, and easy to find. It works well for massage blends and general skincare.
- Coconut oil (unrefined): Rich in fatty acids and polyphenols, making it a good base for massage. Skip refined coconut oil for aromatherapy since it’s been chemically processed and lacks the same skin-nourishing profile.
Before applying any new blend to a large area, do a patch test. Dab a small amount on the inside of your forearm, cover it lightly, and wait 24 hours. If you see redness, itching, or swelling, that blend isn’t right for your skin.
Citrus Oils and Sun Exposure
Certain essential oils, particularly cold-pressed citrus peels, contain compounds called furocoumarins that make skin more sensitive to ultraviolet light. Applying these oils and then heading into the sun can cause burns, blistering, or lasting discoloration.
The most common phototoxic oils are bergamot, bitter orange, grapefruit, lemon, and lime (all expressed from the peel). Bergamot is the most reactive, with a maximum recommended use level of just 0.4% on skin that will be exposed to UV light. Grapefruit is less reactive, with a 4% limit.
The simplest rule: after applying any citrus oil topically, avoid direct sunlight or UV exposure (including tanning beds) for at least 12 hours. Alternatively, look for bergamot labeled “FCF” or “furocoumarin-free,” which has the phototoxic compounds removed and is safe in the sun.
Safety Around Children and Pets
Not every oil that’s safe for an adult is safe for a child. Peppermint oil should not be used on children under 30 months old because it can increase seizure risk in very young children. Citronella, which functions as an insecticide, should be avoided on babies under 6 months.
As a general practice, use lower dilutions for children (0.5% to 1%), diffuse in well-ventilated rooms, and keep bottles stored where small hands can’t reach them. If a child swallows a significant amount of essential oil, contact poison control immediately, offer whole or 2% milk, and do not try to induce vomiting.
Cats are particularly vulnerable because they lack certain liver enzymes needed to metabolize many essential oil compounds. Oils high in phenols, such as tea tree, oregano, and clove, are commonly flagged as problematic. If you diffuse around pets, keep sessions short, ensure the room is ventilated, and give the animal a way to leave the space.
Choosing Quality Oils
The essential oil market is unregulated in many countries, so quality varies enormously. A reliable brand will provide the botanical name of the plant, the country of origin, the extraction method, and ideally, access to GC/MS (gas chromatography/mass spectrometry) test results for each batch.
GC/MS testing separates an oil into its individual chemical components and then identifies each one by its molecular fingerprint. This reveals whether an oil is pure, whether it’s been adulterated with synthetic compounds, and whether its chemical profile matches what that plant species should produce. Many reputable companies post these reports on their websites or provide them on request. If a brand can’t or won’t share testing data, that’s a reason to look elsewhere.
Storing Your Oils
Essential oils degrade with exposure to heat, light, and oxygen. Over time, oxidized oils lose effectiveness and can actually become more likely to irritate skin. Store your bottles upright in a cool, dark location. A refrigerator is ideal. Dark amber or cobalt blue glass bottles block light and are standard for a reason. Always close the cap tightly after use to limit oxygen exposure, and note that citrus oils and tree oils like tea tree tend to oxidize faster than others, so use those within 6 to 12 months of opening.
A Note on Ingesting Essential Oils
Some wellness brands promote adding essential oils to water or food. The National Association for Holistic Aromatherapy does not support the indiscriminate internal use of essential oils and recommends that ingestion only happen under the guidance of a trained professional using products specifically formulated and labeled for that purpose. Essential oils are extremely concentrated. A single drop of peppermint oil is far more potent than a cup of peppermint tea. Swallowing undiluted oils can irritate or damage the mucous membranes of the mouth, esophagus, and stomach. For home aromatherapy, inhalation and properly diluted topical application are the safest and most effective routes.